A new kind of friction-reducing and repairing additive containing nano-scale copper and rare earth compounds were prepared by means of synthesis and compounding methods. The performance of the said additive was invest...A new kind of friction-reducing and repairing additive containing nano-scale copper and rare earth compounds were prepared by means of synthesis and compounding methods. The performance of the said additive was investigated by engine bench test, and was compared to the performance of similar domestic and imported additives. The deterioration of lube oils containing additives over different time intervals was studied by means of plasma spectrometry and mass spectrometry, and the effect of additive package on engine power was also studied. Test results have revealed that the synthetic additive package can provide good anti-wear performance to the tribo-pairs. In particular, after 300 hour application of the said additive package the connection rod shaft and copper sleeve showed 'zero wear' to achieve the in situ dynamic repairing of tribo-pairs. Application of the said synthetic additive can effectively improve the engine power performance and extend the engine service life.展开更多
Caragana korshinskii Kom, which is a kind of excellent shrubs, has strong resistance to windstorms, and it is also a kind of forage that is of high nutritional value as well as a forming fuel conversion resource that ...Caragana korshinskii Kom, which is a kind of excellent shrubs, has strong resistance to windstorms, and it is also a kind of forage that is of high nutritional value as well as a forming fuel conversion resource that is of high caloric. Caragana korshinskii Kom is of high lignifications after growing for a few years and the toughness of it is considerably high. Currently in China, equipments of harvesting and processing for ripe crops can hardly finish the mechanized production for Caragana korshinskii Kom. Friction characteristics of woody material for Caragana korshinskii Kom under different conditions should be given when the relevant operation machinery is designed, which can provide physical parameters for transportation of Caragana korshinskii Kom as well as the designing of relevant machinery. The paper bases on the research of friction characteristics between Caragana korshinskii Kom whose diameter of 7, 10, and 13 mm under sampling directions of 0°, 45°,and 90° and machinery materials that are commonly used such as steel plate, rubber sheet and so on, and meanwhile the test considers factors such as different conditions of Caragana korshinskii Kom, different materials of machines, different angles and so on. The data strongly suggests that the average static, dynamic friction coefficient between Caragana korshinskii Kom and steel plate is 0.399 711 and0.353 022, respectively; The average static and dynamic friction coefficient between Caragana korshinskii Kom and rubber sheet is 0.965 178 and 0.883 667, respectively. The maximum of static and dynamic friction coefficients is when the angle between the direction of sampling and the direction of movement is vertical. As the angle increased, the dynamic and static friction coefficient decreased. The friction coefficient between Caragana korshinskii Kom and steel plate were increased with the increase of the diameter of Caragana korshinskii Kom, but the diameter have no effect on the dynamic friction coefficient between Caragana korshinskii Kom and rubber plate. The conclusion of this paper can provide references for research on machines that are relevant to transportation and particle forming of Caragana korshinskii Kom.展开更多
Effect of slope inclination on step friction coefficient of human being was studied by gait friction tester developed by Henan University of Science and Technology.It is beneficial to improving the safety of human bei...Effect of slope inclination on step friction coefficient of human being was studied by gait friction tester developed by Henan University of Science and Technology.It is beneficial to improving the safety of human beings while walking on a ramp.Based on the trajectory of mass center of body(MCOB)and the mechanical analysis of human body while walking,conclusion could be drawn that the required step frictional coefficient(RSFC)exhibited an"M"shaped curve during the foot contacting with the ground and got its maximum and minimum values when MCOB of the subject was at the highest and lowest position respectively.Moreover,the first peak of RSFC decreases firstly and then increases,while the second peak of RSFC increases with the increase of slope inclination at the experimental condition.The position of pivotal point is decided by the relative size of slope inclination and the angle between the plumb line through MCOB and the line from foot to MCOB.展开更多
文摘A new kind of friction-reducing and repairing additive containing nano-scale copper and rare earth compounds were prepared by means of synthesis and compounding methods. The performance of the said additive was investigated by engine bench test, and was compared to the performance of similar domestic and imported additives. The deterioration of lube oils containing additives over different time intervals was studied by means of plasma spectrometry and mass spectrometry, and the effect of additive package on engine power was also studied. Test results have revealed that the synthetic additive package can provide good anti-wear performance to the tribo-pairs. In particular, after 300 hour application of the said additive package the connection rod shaft and copper sleeve showed 'zero wear' to achieve the in situ dynamic repairing of tribo-pairs. Application of the said synthetic additive can effectively improve the engine power performance and extend the engine service life.
文摘Caragana korshinskii Kom, which is a kind of excellent shrubs, has strong resistance to windstorms, and it is also a kind of forage that is of high nutritional value as well as a forming fuel conversion resource that is of high caloric. Caragana korshinskii Kom is of high lignifications after growing for a few years and the toughness of it is considerably high. Currently in China, equipments of harvesting and processing for ripe crops can hardly finish the mechanized production for Caragana korshinskii Kom. Friction characteristics of woody material for Caragana korshinskii Kom under different conditions should be given when the relevant operation machinery is designed, which can provide physical parameters for transportation of Caragana korshinskii Kom as well as the designing of relevant machinery. The paper bases on the research of friction characteristics between Caragana korshinskii Kom whose diameter of 7, 10, and 13 mm under sampling directions of 0°, 45°,and 90° and machinery materials that are commonly used such as steel plate, rubber sheet and so on, and meanwhile the test considers factors such as different conditions of Caragana korshinskii Kom, different materials of machines, different angles and so on. The data strongly suggests that the average static, dynamic friction coefficient between Caragana korshinskii Kom and steel plate is 0.399 711 and0.353 022, respectively; The average static and dynamic friction coefficient between Caragana korshinskii Kom and rubber sheet is 0.965 178 and 0.883 667, respectively. The maximum of static and dynamic friction coefficients is when the angle between the direction of sampling and the direction of movement is vertical. As the angle increased, the dynamic and static friction coefficient decreased. The friction coefficient between Caragana korshinskii Kom and steel plate were increased with the increase of the diameter of Caragana korshinskii Kom, but the diameter have no effect on the dynamic friction coefficient between Caragana korshinskii Kom and rubber plate. The conclusion of this paper can provide references for research on machines that are relevant to transportation and particle forming of Caragana korshinskii Kom.
基金supported by the National Natural Science Foundation of China(Grant Nos.U1034002 and 51175149)
文摘Effect of slope inclination on step friction coefficient of human being was studied by gait friction tester developed by Henan University of Science and Technology.It is beneficial to improving the safety of human beings while walking on a ramp.Based on the trajectory of mass center of body(MCOB)and the mechanical analysis of human body while walking,conclusion could be drawn that the required step frictional coefficient(RSFC)exhibited an"M"shaped curve during the foot contacting with the ground and got its maximum and minimum values when MCOB of the subject was at the highest and lowest position respectively.Moreover,the first peak of RSFC decreases firstly and then increases,while the second peak of RSFC increases with the increase of slope inclination at the experimental condition.The position of pivotal point is decided by the relative size of slope inclination and the angle between the plumb line through MCOB and the line from foot to MCOB.
